Latch and pivot for folding rules



Feb. 5, 1952 R- E. HOPP LATCH AND PIVOT FOR FOLDING RULES Filed Jan. .29, 1949 6Q v f R Y \&Z g (N v Q W QA N v RN N) ,NSQ w h m3 6Q m \H 1 ww. c aw 712. J o l Q; N 6Q 8/ no \Q w 9 l m% 2 Q E a i Y i Patented Feb. 5, 1952 UNITED STATES PATENT OFFICE Robert Ewing- H'opp, Poughkeepsie, NI Y; as-

signorto. Carlton B. Fi'tchett,v Poughkeepsie,

N. YI

Applicationulanuary 29, 1949, Serial No. 73,649

(Cli'ZST-IOI) 9 Claims.

This invention relates; to. folding rules of. the type made from a plurality of shortsections in the 'form of .thin strips of a solid material, the adjacent end. portions of. which are overlapped andthe strips themselves joined togetherby a pivoting fastener through the overlapped. ends. Rules of. this type may be, ,when the sections thereofare folded together, conveniently carried inztheipocket.

lniparticular; thisinvention relates to a combination/latching and PiV-OtiHgQStI'UCtUIBJOI' joiningtsectionstof afioldingzruleand has iorits main objectto provide arrimproved arrangement of cooperating::partsswhereby the rule sections may bettemporarily secured. in: an i open, closed, or right angular position relative-to eachother withouttdeformation: of any part. ofthe body, of the rule sections.

Another objectrofthisinvention is to provide amimprovedlatch: and-wpivot construction particularly adaptable to: foldingg rules having.- the sectionsthereofjmade .fromaa molded or pressed pl'asticmaterial of high. tensile, compressive; and flexural strength andhaving, in.addition=,.;a-high tough'ness andzhardness characteristic. Onexwell known example of: such; av plastic material is Bakelite.

A: furtherobject of. this--invention is to provide -a..folding rulewhichis inexpensive, durable, and

along the central longitudinal. axis of-the sections and .give .a latching cheat in any oneof. three positions .whereby the rule. sections-may betem- I por-aril-y secured inan open, closed,.or.rig'h't angular arrangement relative. to. each other.

Shrrounding. the hinge pin and'held'in partial compression between oneface .of 'the..overlap'pedfsecti'onsand oneend of'thehinge pinis a tension device, by meansof which'tlie co'operatingjlatching. surfaces are held liniintimate. contact:

I'am aware that folding, rules .o'fjthe type'descr'lb'edin II. Patent No; 496E123 tUK'euiTe'Y'and no; 1538;995"toLakatos'are well known-.- Iii-rules ofthe a'ule sections isformedissuffitientlynerdbleto permit thecooperatinglatching devices to passinto and out of engagement without dama ing-the same or a section end cover is provided of a.-.material which will fiexwithout damage.

5 Othertypes of rules, such as that describedin two-rule sectionsareshown for illustrative purposes and not by way of limitation, a, preferred embodiment ofthe invention is disclosed. It is tobe understood that as many sections as desired maybeused, one section being joinedto the next as described hereinafter. I

Figure .1. is a central. longitudinal view through aiolding rule Witha-joint and latch structure according tothis invention;

Figures 2 and 3. are plan views ona somewhat 5 reduced scale of the upper and lower rule sections respectivelyshown in Figure 1;

Figures 4 and 5-are sectionalviews taken on 1ines 4-4--and.55 of Figured; and

Figures G and 7 are sectional views taken on lines ii-fland'i-i of Figure 3.

Referring; to the drawing in detail, the: rule sections lfl are. formed bypressing or mouldin from: a plastic material having a high tensile, compressive,-

fiexural. strength in addition 40" to :a'high toughness and hardness characteristic.

One imaterial. which hasbeen found to be very satisfactoryfor this' purpose is commonly a known as Bakelitefi? Therulesection members: In are formed.: with cooperating raised and; depressed ;latchingsurtacessl I; I! and l'2,.and i2" respectively' onadjacen't faces at their overlapping ends. Midway of the. cooperating latching surfaces; a hinge-pin l-t is provided, preferably in; the. form of a 'tubul'ar' rivet, to connect the overlapping: end

sections:- Recesses' Mian'd l5, formed in the outside faces oftheoverlapping ends ofthesecti'ons I'U as-shown; areadapted' to receivethe upset ends of the hinge pin and, in this way, a fiat smooth overall surface on the rule is provided.

A tension device l 6; shown in the form of'a lock 'pressive force of the tension device.

washer surrounding the hinge pin, is secured in the final assembly between the outer face of one of the overlapped section ends and one end of the hinge pin.

The side walls of the latching surfaces are formed as sloping sides whereby the rule sections may be easily moved relative to each other from one latched position to another against the com- It is to be noted that the cooperating latching surfaces H, H, 12 and I2 are arranged symmetrically and equidistant from the center of hinge pin [6 along the central longitudinal axis of the rule section members I0. Thus the members will be held against relative turning movement whether the same be in an extended (open) or folded (closed) position.

lhe sloping sides 11, I1 (Fig. 4) of the raised latching surfaces II and H (Fig. 1) are spaced apart a distance substantially equal to the width of the rule sections Hi. In the embodiment shown in the drawing, the raised latching surfaces are formed on the underside of each upper rule section I0. At each pivoted joint, additional sloping sides l8, [8 are provided along each of the upper longitudinal edges of the adjacent face of each lower rule section member l within the longitudinal limits of the overlapped end portions of the members (Figs. 3 and 7) By means of these cooperating sloping sides, the section members If! of the rule may be temporarily secured in a right angular relation.

The operation of the latching and pivoting structure of this invention will be described by reference first to Figure 1 wherein the rule section members ID are shown in an extended (open) position and raised surfaces II and I l' of the up-.

per rule section are received within the recessed surfaces i2 and [2 of the lower rule section ill. The sections are held in this interfitting relation by the partial compression of the tension device IS. A movement of either section it) relative to the other will result in sliding the sloping sides against each other and further compression of the tension device Hi. If, for example, the movement of the upper rule section If] relative to the lower section II] is continued in a clockwise direction, the raised surfaces H and I l of the upper section l0 will ride up to and pass over the smooth portions of the adjacent face of the lower section In. When the relative movement of the rule sections approaches 90, sloping sides l7 and ll of the raised surfaces H and II respectively (Fig. 4) will reach and begin to ride down the sloping sides I8 and I8 (Figs. 3 and '7) formed along the outside edge of the adjacent face of the lower rule section [0. Thus, when the rule sections have been moved to the 90 relation, these last mentioned sloping sides will interfit and the rule section members will be temporarily secured under the partially released compressive force of tension device It. Further movement of the rule sections in the same direction relative to each other will disengage the sloping sides l1, ll of raised surfaces II and II on the upper section member from the sloping outside edges l8, [8 of the lower section, and upon completion of the second 90 degrees of rotation, the sections will interlock in the folded (closed) position, in which the cooperating raised and lower surfaces H, 12 and H, 12, respectively, interfit and temporarily secure the rule sections under the compressive force of the tension device 16.

From the above description of the invention, it

.will be seen that the latching and pivoting arrangement will provide a temporary securing means for the rule section members whereby the same may be held in any one of the three predetermined positions relative to each other, and that the section members can be moved into and out of these positions without deformation of any part of the body of the sections. In view of this latter characteristic of the invention, it will be seen that the latching and pivoting arrangement is particularly adaptable to rules having the section members thereof molded or pressed from Bakelite or a like non-deformable plastic material.

It will also be seen that the simplicity of the manner in which the section members can be assembled will materially aid in reducing the cost of manufacturing rules of this'type.

I claim:

1. A latch and pivot structure of the class described comprising a pair of rigid fiat section members having overlapping end portions, a hinge pin having upset ends arranged through the overlapped portions of the members whereby the said members are pivotally connected, a pair of rigid raised symmetrical surfaces having sloping sides extending from each surface to the body formed on one of the members on one face thereof, a pair of depressed surfaces having sloping sides formed in the body of and on the adjacent face of the other of the said members, said sloping sided depressed surfaces having a configuration complementary to and interfitting with the said sloping sided raised surfaces, the units of the said complementary pairs of raised and depressed surfaces being spaced equidistant from the hinge pin on opposite sides thereof and along the central longitudinal axis of each of the members, and a tension means interposed between one upset end of the said hinge pin and the adjacent face of one of the said members.

' jacent sloping sides of the pair of raised surfaces is substantially equal to the width of the section members.

4. A latch and pivot structure according to claim 1 including also sloping sides, complementary to and adapted to interfit with the adjacent 4 sloping sides of the pair of raised surfaces formed on one of the members, arranged along the outside edges of the adjacent face of the other of the members and within the longitudinal limits of the overlapped end portion of the said other member.

-5. A latching structure, adapted for use with a pivot joint, said joint including a pair of'substantially fiat section members having overlapped end portions, the body of said members being of a non-deformable material, and am upset hinge pin arranged through the overlapped portions whereby the members are pivotally connected, comprising a pair of non-deformable symmetrical raised surfaces formed on one of the adjacent faces of the members within the longitudinal limits of the overlapped end portions thereof, a pair of non-deformable depressed surfaces formed on the other of the adjacent complementary to and interfitting with the said raised surfaces, the units of the pairs of said raised and depressed surfaces being spaced equidistant on opposite sides of the hinge pin and along the central longitudinal axis of the members, and a deformable tension means interposed between one end of the upset hinge pin and the body of one of the members.

6. A latching structure according to claim 5 in which the said raised and depressed surfaces have sloping sides extending therebetween and the said faces of the members.

7. A latching structure according to claim 5 in which the sides of the members adjacent the upset ends of the hinge pin are recessed at the point of passage of the hinge pin therethrough, the

said upset ends being arranged in said recesses,

and in which the tension means is also arranged in one of the said recesses.

8. A latching structure according to claim 5 in which the distance between the adjacent sloping sides of the pair of raised surfaces is substantially equal to the width of the section members.

9. A latching structure according to claim 5 ineluding also sloping sides, complementary to and adapted to interfit with the adjacent sloping sides of the pair of raised surfaces formed on one of the members, arranged along the outside edges of the adjacent face of the other of the members and Within the longitudinal limits of the overlapped end portion of the said other member.

ROBERT EWING HOPP.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

